The aim of this work was to evaluate the inoculum addition on the anaerobic digestion of dairy cattle manure recycled in batch digesters by biogas yield, volatile solids reduction and biogas potential production to obtain design parameters. Twelve field batch digesters (60 L each) filled with dairy catlle manure, water and four different inoculum additions (0, 20, 30 and 40%, v/v) were used. Average times of hydraulic retention of 75 and 150 days were adopted for treatments with and without inoculum, respectively, during three periods of the year (intermediary, rainy and dry). The greatest daily biogas yields occurred in higher room temperatures (rainy period). Higher biogas potential production was obtained by using 40% of inoculum, 0.07 m³ kg-1 manure, with rapid use of biogas from the four days. Times of hydraulic retention of 45 days may be adopted, which reduces the volume of the digester and the implementation costs.
rainy period; dry period; potential; biogas production; reductions
